Platelet‐rich plasma serotonin levels in chronic myeloproliferative disorders: evaluation of diagnostic use and comparison with the neutrophil PRV‐1 assay

Abstract

In a prospective study of 109 subjects, an enzyme‐linked immunosorbent assay (ELISA) was used to measure platelet‐rich plasma (PRP) serotonin levels in patients with polycythaemia vera (PV; n = 27), essential thrombocythaemia (ET; n = 14), myelofibrosis with myeloid metaplasia (MMM; n = 30), secondary or spurious polycythaemia (SP; n = 22) and controls (n = 16). Nine study subjects who were taking a selective serotonin reuptake inhibitor (SSRI) all displayed a markedly decreased PRP serotonin level (median, 24·2 ng/10⁹ platelets; range, 0–49·3) and were therefore excluded from further analysis. Among the remaining 100 subjects, the median and range of PRP serotonin levels, in ng/10⁹ platelets, was significantly lower in MMM (89·5; 0–278·3), PV (204·8; 0–496·0) and ET (385·3; 136·8–1025·7) compared with both SP (608·8; 369·0–1780·1) and controls (567·2; 359·9–1071·1). Neutrophil polycythaemia rubra vera‐1 (PRV‐1) expression was concurrently assayed by real‐time polymerase chain reaction in 69 patients (23 PV, 17 SP, 12 ET, seven MMM, 10 controls). PRP serotonin measurement performed as well as the PRV‐1 assay in distinguishing PV from SP (93% vs. 86% test accuracy). The current study suggests that PRP serotonin concentration might be considered as one of the several biological markers that complement each other for the diagnosis of PV.